Free Base64 Encoder & Decoder Online
Our free online Base64 encoder and decoder lets you instantly convert plain text to Base64 format or decode any Base64 string back to readable text — all within your browser, with no server involved and no data stored. Simply paste your text, select encode or decode, and get your result in one click with this amazing tool.
What is Base64 Encoding?
Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format. It was designed to allow binary content — such as images, audio files, or executable code — to be safely transmitted over channels that only handle text, such as email or HTTP headers. The name “Base64” comes from the fact that it uses 64 printable ASCII characters to represent the encoded data.
The Base64 alphabet consists of the letters A-Z, a-z, the digits 0-9, and the symbols + and /. Every three bytes of binary input are encoded as four Base64 characters, which means Base64-encoded data is approximately 33% larger than the original binary data. The = character is used as padding at the end of the encoded string when the input length is not a multiple of three.
Base64 encoding is used heavily in web development and security. It appears in data URIs for embedding images directly in HTML or CSS, in JSON Web Tokens (JWTs) for API authentication, in HTTP Basic Authentication headers, and in email attachments (via MIME encoding). Understanding Base64 is an essential skill for any developer working with APIs, authentication systems, or web performance optimization.
How to Use the Base64 Encoder/Decoder
- To Encode:Make sure “Encode” is selected in the toggle at the top. Paste or type your plain text into the input box. Click “Run”. Your Base64 encoded string will appear in the output box. Click “Copy Output” to copy it.
- To Decode:Click “Decode” in the toggle. Paste your Base64 string into the input box. Click “Run”. The decoded plain text will appear in the output. If the input is not valid Base64, an error message will be shown.
- Swap:Click the “⇅ Swap” button to move the output back into the input and automatically switch modes — great for quickly verifying an encode-decode round trip.
Frequently Asked Questions
What is Base64 used for?
Base64 is used to encode binary data as text so it can be safely transmitted over text-based systems. Common uses include embedding images in HTML/CSS as data URIs, encoding credentials in HTTP Basic Auth headers, and representing binary data in JSON payloads.
Is Base64 the same as encryption?
No. Base64 is an encoding scheme, not encryption. It does not provide any security — anyone can decode a Base64 string without a key. Do not use Base64 to secure sensitive data.
Why does Base64 output end with = or ==?
The equals sign is used as padding. Base64 encodes data in groups of 3 bytes. If the input is not a multiple of 3 bytes, one or two = characters are added to fill the final group.
Why is my decoded output showing strange characters?
This usually means the Base64 string you pasted contains characters outside the valid Base64 alphabet, or the original data was binary (not plain text) before encoding. This tool is optimized for encoding and decoding text strings.
How often are new tools added?
We add new developer tools regularly based on community feedback. Bookmark the homepage to stay updated on new additions each month.
Is my data secure when using this tool?
Yes. All encoding and decoding is done entirely in your browser. No data is sent to our servers at any point.